* {
    margin: 0;
    padding: 0;
}
.banner {
    width: 100%;
    margin-top: 100px;
    background-color: rgb(18, 18, 18);
}
.main-img {
    width: 100%;
    height: 550px;
    position: relative; 
}
.main-img img {
    width: 80%;
    position: absolute; 
    left: 50%; 
    top: 50%;
    transform: translate(-50%, -50%); 
}
.center-img {
    width: 4%;
    position: absolute; 
    left: 50%; 
    top: 50%;
    transform: translate(-50%, -50%); 
}
.banner-txt {
    z-index: 1;
    font-size: 20px;
    line-height: 100px;
    color: white;
    height: 100px;
    background-color: rgba(0,0,0,.5);
    text-align: center;
    width: 100%;
    position: absolute;
    left: 50%; 
    top: 100%;
    transform: translate(-50%, -100px); 
}
.container {
    margin-top: 20px;
}
.container-text {
    width: 100%;
    font-size: 18px;
    text-align: center;
    color: #b4b4b4;
    padding:5% 0;
}
.img-responsive {
    position: relative;
    width: 100%;
    text-align: center;
    background-color: rgb(18, 18, 18);
}
.zhongxin-img {
    width: 5%;
    position: absolute; 
    left: 0; 
    top: 0;
    right: 0;
    bottom: 0;
    margin: 25% 50%;
}
.center {
    width: 5%;
    position: absolute; 
    left: 0; 
    top: 0;
    right: 0;
    bottom: 0;
    margin: 25% 50%;
    display: none;
}
#img1 {
    width: 29px;
}